feat: update environment configuration and seed admin user in database

nest-backend/src/index.ts

@@ -1,8 +1,36 @@
 import 'dotenv/config';
+import bcrypt from 'bcryptjs';
+import prisma from './lib/prisma.js';
 import app from './app.js';
 
 const PORT = parseInt(process.env.PORT ?? '3000', 10);
 
-app.listen(PORT, () => {
-  console.log(`[server] Running on http://localhost:${PORT}`);
-});
+async function ensureAdmin(): Promise<void> {
+  const { ADMIN_USERNAME, ADMIN_EMAIL, ADMIN_PASSWORD } = process.env;
+  if (!ADMIN_USERNAME || !ADMIN_EMAIL || !ADMIN_PASSWORD) return;
+
+  await prisma.user.upsert({
+    where: { email: ADMIN_EMAIL },
+    update: { username: ADMIN_USERNAME, role: 'dev', isAdmin: true },
+    create: {
+      username: ADMIN_USERNAME,
+      email: ADMIN_EMAIL,
+      password: await bcrypt.hash(ADMIN_PASSWORD, 10),
+      role: 'dev',
+      isAdmin: true,
+    },
+  });
+
+  console.log(`[server] Admin user ready: ${ADMIN_USERNAME}`);
+}
+
+ensureAdmin()
+  .then(() => {
+    app.listen(PORT, () => {
+      console.log(`[server] Running on http://localhost:${PORT}`);
+    });
+  })
+  .catch((err) => {
+    console.error('[server] Startup error:', err);
+    process.exit(1);
+  });